- STRUCTURE
 
- SYNOPSIS
 
Theorem-tactical which always fails.
 
- DESCRIPTION
 
When applied to a theorem-tactic and a theorem, the theorem-tactical
NO_THEN always fails with string `NO_THEN`.
 
- FAILURE
 
Always fails when applied to a theorem-tactic and a theorem (note that it
never gets as far as being applied to a goal!)
 
- USES
 
Writing compound tactics or tacticals.
 
- SEEALSO